Which Characters Are Popular In Supernatural Fanfiction Crossover Pairings?

From what I've seen browsing Archive of Our Own tags, the popularity really depends on which fandoms are currently hot in mainstream media. When 'Stranger Things' had its last season, Eleven and Vecna started appearing in all sorts of supernatural crossovers, especially with 'Hellboy' or 'Supernatural' itself. Now, with the new 'Interview with the Vampire' series, Lestat and Louis are having a resurgence—I've seen them tangled up with 'What We Do in the Shadows' characters, which is either a genius comedic move or a tonal disaster waiting to happen.

Characters who are already portals between worlds, like the Doctor or Dream of the Endless, get used a lot too, but sometimes that feels like cheating because their canon explains the crossover too easily. I prefer when writers take someone rooted in one specific supernatural system and force them to adapt to another—like throwing Percy Jackson into the world of 'The Mortal Instruments' and watching him try to figure out why his ocean powers don't work the same way. Those clashes of lore are where the interesting character moments happen, not when you use an established dimension-hopper.

Buffy Summers remains a crossover staple. She's the blueprint for the snarky supernatural heroine, so dropping her into other monster-filled worlds feels natural. I keep finding fics where she's fighting alongside the Winchester brothers or comparing stakes with Blade. Her popularity hasn't really dipped, she's just reliable.

Two names keep bouncing around the supernatural crossover space lately: Castiel from 'Supernatural' and Geralt from 'The Witcher'. It's weird how well they click in fics even though their worlds operate on different rules—one's all angels and demons, the other's mutations and political intrigue. I think the appeal comes from putting these stoic, duty-bound outsiders together; they both carry that 'ancient warrior in a modern-ish world' vibe but express it so differently. You get Geralt's gruff practicality bouncing off Cas's literal-minded confusion about human things, which writers use to explore themes of found family or what 'humanity' even means.

Lately there's been a surge in crossovers with 'Jujutsu Kaisen' too, probably because the power systems have clear rules that can clash or merge in interesting ways. Gojo Satoru gets tossed into everything from 'The Magnus Archives' to 'Hellboy'—his overpowered, playful attitude creates chaos when he interacts with more grim settings. I'm less convinced by some of the vampire crossover trends; pairing Buffy with 'Twilight' characters feels like a decade-old debate nobody asked to revive.

Honestly though, the real enduring favorite has to be John Constantine. He's the perfect bridge character for any supernatural 'verse because he's already a cynical bastard who jumps dimensions in canon. I've seen him argue with Dean Winchester, reluctantly team up with Harry Dresden, and even annoy the Sandman. He brings a consistent tone of gritty irreverence that grounds even the most high-concept mashup.

It's still Dean Winchester, let's be real. No matter what fandom you drop him into—'The Witcher,' 'Good Omens,' 'Teen Wolf'—he just fits. Maybe it's the leather jacket and the attitude; he's got that recognizable monster-hunter swagger that translates anywhere. I've read crossovers where he's chasing demons in 'Buffy' and ones where he's grudgingly accepting help from 'Doctor Who,' and they all work because his character voice is so strong. Sam shows up sometimes too, but Dean's the one who really anchors these stories for me.

Lately I've noticed more Hermione Granger popping up in supernatural crossovers, which makes sense if you think about it. She's the logical, research-driven witch who would absolutely be investigating ghost phenomena or trying to classify different vampire subspecies. Saw a surprisingly good fic where she teamed up with Fox Mulder from 'The X-Files' to debunk a magical creature sighting, and their dynamic was all tense, intellectual curiosity. I think characters who bring a methodical approach to chaos naturally slot into these mashups.